Hi guys im on the final stage off my final year project only ive made a pretty big mistake.. Ive ordered the completly wrong crystal and i was hoping someone could give me a hand in creating a 640Khz signal..

Its a data logger with wireless communications involved so im using the 11.0592Mhz crystal too run my 8955.. However the ADC im using runs on clock frequencys off between 10Khz and 1.2Mhz.. However there data sheet uses 640Khz as the ideal value and ive been basing my calculations for delays etc using those values at 640..

From research done myself im guessing a 1Mhz crystal divided frequency using a flip flop or the 555 timer has anyone got anyother ideas..